Optimization system and methods for  furnaces, heat pumps and air conditioners

ABSTRACT

Systems and methods for optimizing system efficiency and demand response performance for variable-fan-speed and variable-capacity air handling systems. A controller is provided selectively controlling building-zone dampers in response to acquired operational parameters, such that air flows through selected duct sections and not through the entire duct system simultaneously, wherein design velocity in each duct section is roughly maintained whenever the duct section is being used. Exemplary operational parameters include compressor speed, cooling capacity, heating capacity, fan speed, duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of U.S. provisional patent application Ser. No. 62/478,135 filed on Mar. 29, 2017, incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

A portion of the material in this patent document may be subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. § 1.14.

BACKGROUND 1. Technical Field

The technology of this disclosure pertains generally to heating and cooling equipment, and more particularly to optimization systems and methods for heating and cooling equipment.

2. Background Discussion

Existing controls for variable capacity heating and cooling equipment do not consider changes in the performance of the duct system associated with changing the speed of the fan and changing the heating/cooling capacity of the equipment. Thus, current control strategies result in dramatically sub-optimal performance (energy efficiency and comfort).

FIG. 1 shows measured performance of a state of the art residential, split-system, variable-capacity air conditioner operated with a typical duct system (R-6) located in the same temperature condition as the outdoor unit. This figure shows that reducing capacity and fan speed initially increases system efficiency (cooling at grilles) under mild conditions, but decreases system efficiency once the capacity/fan-speed drops below a certain level. As the duct-zone temperature increases, the optimal capacity/fan-speed increases, reaching 100% somewhere between 105° F. and 115° F. in the duct zone. Many ducts in existing homes are in attics, where temperatures typically exceed outdoor temperature.

BRIEF SUMMARY

The technology of this disclosure solves problems associated with current equipment control strategies by characterizing duct system performance with a few readily available parameters, and using a simplified algorithm to adjust equipment operating parameters (fan speed, capacity, and damper positions). In general terms, this disclosure describes a methodology for controlling a variable speed heat pump, furnace or air conditioner to maximize the overall efficiency of the entire system. In one embodiment, this is accomplished by managing fan speed, compressor/burner capacity, and a zone-damper system, to optimize system efficiency by considering thermal losses from ducts, fan power and compressor efficiency. The technology requires minimal changes in hardware (e.g. in some embodiments one or more additional temperature sensors), but has the capability to increase system efficiency by 20-300%, depending upon conditions, as a result of the joint optimization of performance.

Further aspects of the technology described herein will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the technology without placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The technology described herein will be more fully understood by reference to the following drawings which are for illustrative purposes only:

FIG. 1 is a plot showing measured performance of a state of the art residential, split-system, variable-capacity air conditioners operated with a typical duct system (R-6) located in the same temperature condition as the outdoor unit.

FIG. 2 is a schematic system diagram of a system for improving the energy efficiency and comfort performance of variable-speed/capacity heating and cooling equipment.

FIG. 3 is a schematic system diagram of an alternative system for improving the energy efficiency and comfort performance of variable-speed/capacity heating and cooling equipment without use of sensors.

FIG. 4 shows a schematic flow diagram of a capacity-based zone cycling method for improving the energy efficiency and comfort performance of variable-speed/capacity heating and cooling equipment.

FIG. 5 shows a schematic flow diagram of one embodiment of the cycling step of FIG. 4.

FIG. 6 shows a temperature and capacity based zone cycling method for improving the energy efficiency and comfort/performance of variable-speed/capacity heating and cooling equipment.

FIG. 7 is a plot showing measured duct delivery effectiveness vs. synchronized reductions in compressor and fan speed for various temperatures.

FIG. 8 is a plot showing system-efficiency improvements for a capacity-based method for improving the energy efficiency and comfort/performance of variable-speed/capacity heating and cooling equipment via zone cycling.

FIG. 9 is a plot showing delivery efficiency vs. temperature for various zone-damper operating modes.

DETAILED DESCRIPTION

In general terms, the technology of the present description includes systems and methods for characterizing duct system performance via a few readily available parameters, and using a computerized controller with computer program instructions that adjust equipment operating parameters (fan speed, capacity, and damper positions) to optimize system performance. FIGS. 2 and 3 show schematic diagrams of two systems for improving the energy efficiency and comfort performance of variable-speed/capacity heating and cooling equipment. FIG. 4 through FIG. 6 show various methods, by way of example, and not of limitation, that may be implemented as instructions for controlling (i.e. adjusting operating parameters) the systems shown in FIG. 2 and FIG. 3.

It is appreciated that the systems and methods disclosed herein may be used with various Heating, Ventilation, and Air Conditioning (HVAC) systems, also herein referred to as air handling system, which may include but are not limited to: furnaces, heat pumps, air conditioners, or the like. It is also appreciated that while certain systems and/or methods may be described herein with respect to a particular implementation or embodiment (e.g. cooling protocol for an air conditioning system), any of the embodiments and methods may be variously interchangeable with any HVAC system, method, or component thereof.

Referring to FIG. 2, a system 10 is shown for improving the energy efficiency and comfort and/or performance of variable-speed/capacity heating and cooling equipment. FIG. 2 and FIG. 3 show schematic diagrams of the system of the present description. Components detailed therein are not to scale, and any relative placement, orientation, or grouping of components shown therein may be modified, interchanged, duplicated or removed in various preferred embodiments according to the type of heating, ventilation or cooling system and space, building or environment to be conditioned.

The system 10 generally comprises an air-handling or HVAC unit 12 having a burner/compressor 34 for conditioning the air and fan 32 for moving air from return plenum 16 to the supply plenum 18. A system controller 14, (e.g. computer, controller or the like processing device) is coupled to the HVAC unit 12 and comprises a processor 40, and application software 42 stored in memory 44 and executable on the processor 40 for controlling operation of one or more components within the system 10. The controller 14 is also coupled to one or more dampers 20 located at or downstream from the supply plenum 18. The controller 14 is configured to operating the dampers 20 to control distribution to a plurality of duct sections 22, 24, and 26 that distribute the conditioned air to the building via a plurality of grilles 25. While three duct sections 22, 24, and 26 are shown in FIG. 2, it is appreciated that any number, shape, or orientation may be employed to the duct sections and/or grilles 25.

The controller 14 may optionally be coupled to one or more sensors (e.g. temperature and/or pressure sensors or the like) located in the system 10 for providing feedback on system operation/performance. In one embodiment, sensors 30 a and 30 b are positioned at or near the return plenum 16 and supply plenum 18, respectively. In another embodiment, sensors 30 c are positioned within the duct sections 22, 24, and 26 and/or sensors 30 d at or near grilles 25.

FIG. 3 is a schematic system diagram of an alternative system 50 for improving the energy efficiency and comfort and/or performance of variable-speed/capacity heating and cooling equipment without use of sensors. In system 50, the controller 14 is configured to operating the dampers 20 to control distribution to a plurality of four duct sections 22, 24, 26, and 28 that distribute the conditioned air to the building via a plurality of grilles 25 without the use of sensors. While four duct sections 22, 24, 26, and 28 are shown in FIG. 3, it is appreciated that any number, shape, or orientation may be employed to the duct sections and/or grilles 25.

The system 50 generally comprises an HVAC unit 12 having a burner/compressor 34 for conditioning the air and fan 32 for moving air from return plenum 16 to the supply plenum 18. A processing unit 14, (e.g. computer, controller or the like) is coupled to the HVAC unit 12 and comprises a controller/processor 40, and application software 42 stored in memory 44 and executable on the controller 14 for controlling operation of one or more components within the system 10.

Application software 42 may comprise instructions in the form of machine readable code for operating systems 10 and/or 50 an accordance with the following exemplary control methods.

FIG. 4 shows a schematic flow diagram of a first example of a capacity-based zone cycling method 60 for improving the energy efficiency and comfort/performance of variable-speed/capacity heating and cooling equipment without use of sensors, e.g. via a system such as the system 50 shown in FIG. 3. Algorithm 1 (detailed below) also provides an exemplary algorithm or logic flow for computer readable instructions the may be implemented as code for application software 42 for implementation of method 60 in a system having three duct sections in accordance with the present description. Zone/section dampers 20 are controlled such that when capacity is reduced (e.g., when compressor 34 speed is reduced), all air goes through one, two or three of the duct sections 22, 24 and 26 (versus the entire system), sequencing through all building zones calling for conditioning, and roughly maintaining design velocity in each duct section whenever it is being used and at all fan/capacity reduction levels. The “zone cycling” approach of method 60 avoids thermal losses through duct sections that are not being used at that time, while also considering static pressure and fan 32 power.

Referring to FIG. 4, after system start at 61, thermostats at the various zones provide data to the controller 14, and a determination is made at step 62 as to which zones need conditioning. At step 64, one or more dampers 20 are opened or closed based on which zone or zones were determined to need conditioning in step 116. At step 66, compressor 34 and/or fan 32 speed are set according to a desired percentage of operation flow for the allocated zone or zones.

At step 68, an assessment is made as to whether a call for capacity reduction is made on the unit 12. Capacity reduction may be requested from either a local utility providing power to the unit 12, or within programming inherent to the unit 12 itself. If no capacity reduction is requested, then the routine loops back to zone conditioning step 62.

If capacity reduction is requested, a determination is made at step 70 as to whether the requested capacity reduction (e.g. demand-response event asking for a certain percentage curtailment of power draw) is less than the combined capacity of the zones being allocated. If the requested capacity reduction is less than the combined capacity of the zones delivering air, then the routine loops back to zone conditioning step 62 until a requested capacity reduction is found to be greater than the combined capacity of the zones being allocated. At that point, the proper zone cycling scheme is employed at 72. The zones are then measured again at step 114 for further iterations.

FIG. 5 shows an exemplary zone cycling step 72 for a system having 3 ducts, wherein all three ducts are being allocated for delivery of conditioned air. It is appreciated that zone cycling step 72 may vary depending on the combination of zone called on for air conditioning, see logic flow of Algorithm 1. In the exemplary configuration of FIG. 5, dampers to zones 2 and 3 are closed at step 74 (while zone 1 remains running) for a specified period of time T (or lesser time if zone 1 is no longer called for conditioning). At step 76, dampers to zones 1 and 3 are closed while the damper to zone 2 is opened for time T (or lesser time if zone 2 is no longer called for conditioning). Finally, at step 78, dampers to zones 1 and 2 are closed while the damper to zone 3 is opened for time T (or lesser time if zone 3 is no longer called for conditioning). Upon completion of the cycle, the routine loops back to zone conditioning step 62.

Algorithm 1:

Definitions

Cap1: Capacity and air flow associated with design flow for Zone 1

Cap2: Capacity and air flow associated with design flow for Zone 2

Cap3: Capacity and air flow associated with design flow for Zone 3

CAPT: Total capacity and flow (in this case Cap1+Cap2+Cap3)

D1: Damper to Zone 1

D2: Damper to Zone 2

D3: Damper to Zone 3

Condition A: Zone 1 calls for conditioning

Condition B: Zone 2 calls for conditioning

Condition C: Zone 3 calls for conditioning

CAPRED: Utility or internal equipment logic calls for capacity reduction implies CAPRED=TRUE

CapX: Reduced capacity called for when CAPRED=TRUE

IF A AND NOT CAPRED

Operate at (Cap1) D2=Closed D3=Closed

IF B AND NOT CAPRED

Operate at (Cap2) D1=Closed D3=Closed

IF C AND NOT CAPRED

Operate at (Cap3) D1=Closed D2=Closed

IF A AND B AND NOT CAPRED

Operate at (Cap1+Cap2) D3=Closed

IF A AND C AND NOT CAPRED

Operate at (Cap1+Cap3) D2=Closed

IF B AND C AND NOT CAPRED

Operate at (Cap2+Cap3) D1=Closed

IF A AND B AND C AND NOT CAPRED

Operate at CAPT

In a situation where Utility or internal equipment logic calls for capacity reduction to CAPRED

IF A AND CAPRED

Operate at (Cap1) D2=Closed D3=Closed

IF B AND CAPRED

Operate at (Cap2) D1=Closed D3=Closed

IF C AND CAPRED

Operate at (Cap3) D1=Closed D2=Closed

IF A AND B AND CAPRED

D3=Closed If CapX<(Cap1+Cap2)

Operate at (Cap1) for the lesser of time T (OR until A is FALSE) with D2=closed

THEN

Operate at (Cap2) for the lesser of time T (OR until B is FALSE) with D1=closed

ELSE Operate at (Cap1+Cap2)

IF A AND C AND NOT CAPRED

D2=Closed If CapX<(Cap1+Cap3)

Operate at (Cap1) for the lesser of time T (OR until A is FALSE) with D3=closed

THEN

Operate at (Cap3) for the lesser of time T (OR until C is FALSE) with D1=closed

ELSE Operate at (Cap1+Cap3)

IF B AND C AND NOT CAPRED

D1=Closed If CapX<(Cap2+Cap3)

Operate at (Cap2) for the lesser of time T (OR until B is FALSE) with D3=closed

THEN

Operate at (Cap3) for the lesser of time T (OR until C is FALSE) with D2=closed

ELSE Operate at (Cap2+Cap3)

IF A AND B AND C AND CAPRED

Operate at (Cap1) for the lesser of time T (OR until A is FALSE) with D2=closed AND D3=closed

THEN

Operate at (Cap2) for the lesser of time T (OR until B is FALSE) with D1=closed AND D3=closed

THEN

Operate at (Cap3) for the lesser of time T (OR until C is FALSE) with D1=closed AND D2=closed

One exemplary configuration of the system-efficiency improvements of method 60 may be implemented in a system 50 (FIG. 3) operating at 2000 cfm (@ 100% operation) with variable-capacity heat pump 12 serving 4 building zones serviced by duct sections 22 through 28 (Zone 1 moves 800 cfm, Zone 2 to Zone 4 each move 400 cfm, wherein each zone can call for conditioning separately), having control logic parameters as follows:

A) If one zone calls for conditioning:

-   -   i. open the damper 20 for that zone;     -   ii. set the compressor 34 and fan 32 speed to the fraction of         the 100% operation flow represented by that zone (i.e. 40% for         Zone 1, 20% for other Zones).

B) If more than one zone calls for conditioning:

-   -   i. open the dampers 20 for all zones calling for conditioning;     -   ii. Set the compressor 34 and fan 32 speed to the fraction of         the 100% operation flow represented by the sum of all zones         calling for conditioning (e.g. 60% for Zone 1 plus Zone 3).

C) If there is a demand-response event asking for a 60% curtailment of power draw (i.e. 40% compressor speed) and two zones call for conditioning:

-   -   i. set the compressor 34 and fan 32 speed to 40%;     -   ii. if it is some combination of Zones 2, 3, 4:         -   1. open the dampers for the two zones calling for             conditioning;     -   iii. if it is a combination Zone 1 plus one of Zones 2, 3, 4:         -   1. open the damper for Zone 1 for 6 minutes, and then close             that damper; and         -   2. open only the damper for the other zone calling for             conditioning for 6 minutes while reducing the fan and             compressor to 20%;         -   3. alternatively (e.g. if the compressor cannot operate at             20%), open the dampers to two of the 20% zones, one being             the zone calling for conditioning, and the other not.

When cycling the zone dampers 20 to condition more than one building zone at reduced capacity, the duct section serving each building zone can be activated for time T lasting several minutes (e.g. 5-15 minutes) to minimize cycling losses (although the control could also include zone over-run to capture heating or cooling in the duct mass).

In an alternative embodiment, the duct sections can be cycled through more quickly (e.g. 2-5 minutes) to provide less swing in building-zone temperatures (although this will be less efficient).

Method 60 may also include a building-zone prioritization scheme (e.g. varying time T for cycling steps 74 through 78). Method 60 may also be implemented based upon a duct efficiency model that can be used to calculate and optimize overall system efficiency.

The capacity-based zone cycling method 60 minimizes duct thermal losses (without using excessive fan 32 power) at any given capacity while maintaining the desired reduction in heating or cooling capacity (e.g. to increase equipment efficiency and/or limit electrical power draw). This contrasts with conventional systems where the entire duct system is used simultaneously.

FIG. 6 shows a schematic flow diagram of a temperature and capacity-based zone cycling method 80 for improving the energy efficiency and comfort performance of variable-speed/capacity heating and cooling equipment. In method 80, sensor data, such as the measured or predicted duct zone temperature, along with the duct insulation R-value (and possibly zone layout for more precision), are used to determine when to utilize zone cycling. In a preferred embodiment, method 80 is implemented in a system such as system 10 shown in FIG. 2, wherein one or more sensors 30 a, 30 b, 30 c and 30 d may be used to provide additional optimization to the system.

Referring to FIG. 6, after system start at 82, a determination is made at step 84 as to which zones need conditioning (e.g. from data provided by one or more thermostats (not shown) in the zones). At step 86, one or more dampers 20 are opened or closed based on the conditioning zones determined in step 116. At step 88, burner/compressor 34 and/or fan 32 speed are set according to a desired percentage of operation flow for the allocated zone or zones.

At step 90, an assessment is made as to whether a call for capacity reduction is made on the unit 12. Capacity reduction may be requested from either a local utility providing power to the unit 12, or within programming inherent to the unit 12 itself. If no capacity reduction is requested, then the routine loops back to zone conditioning step 84.

If capacity reduction is requested, a determination is made at step 90 as to whether the requested capacity reduction (e.g. demand-response event asking for a certain percentage curtailment of power draw) is less than the combined capacity of the zones being allocated. If the requested capacity reduction is less than the combined capacity of the zones delivering air, then the routine loops back to zone conditioning step 84 until a requested capacity reduction is found to be greater than the combined capacity of the zones being allocated.

If the requested capacity reduction is less than the combined capacity of the zones delivering air, a determination is then made at step 92 that takes into consideration temperature data provided by one or more of sensors 30 a, 30 b, 30 c, and 30 d as to whether a temperature defect threshold has been met. If a specified temperature defect is within threshold the routine loops back to zone conditioning step 84. If the specified temperature defect is outside a given threshold, then a zone cycling process, such cycling process 80 detailed in FIG. 5 or any of the processes detailed in Algorithm 1 are used to cycle the delivery to one or more of the allocated duct sections 22, 24 and 26. In one exemplary cooling configuration, the building-zone cycling process 94 is be initiated whenever the duct-zone temperature (e.g. measured via sensors 30 c) exceeds 95° F. for R-6 ductwork or 90° F. for R-4 ductwork.

After the proper zone cycling scheme 94, the routine loops back to zone conditioning step 84.

The method 80 may also be variably configured based upon the duct system design and location, measured or predicted temperatures in the duct zones/sections 22, 24, 26, and/or based upon a duct efficiency model that can be used to calculate and optimize overall system efficiency.

In a further refinement of the above disclosed embodiments, the methods 60 or 80 may be modified to specify conditions where the indoor fan 32 speed is decreased less than the decrease in compressor 34 speed or system capacity (this may result in an increase in fan speed depending on the specified capacity decrease). Keeping the fan speed reduction less than the capacity reduction reduces the residence time in the ductwork and the temperature difference across the duct walls, thereby reducing thermal losses. Although this increases fan power, the increase in fan power can be more than compensated for by increases in delivery effectiveness. It also impacts the sensible heat ratio, so its use can also better address low-humidity cooling loads, but can be constrained by high-humidity cooling loads. The above fan speed manipulation may be implemented based upon the duct system design and location, measured temperatures in the duct zone or grilles (e.g. with sensors 30 c and 30 d, respectively), and/or based upon a duct efficiency model that can be used to calculate and optimize overall system efficiency.

In yet a further refinement, the temperature and capacity-based zone cycling method 80 of FIG. 6 may incorporate sensor measurements of temperature at some (or all) grilles 25. In a preferred embodiment, the algorithm optimizes overall system efficiency based upon measured differences between grille temperatures (e.g. at sensors 30 d) and the supply plenum temperature (e.g. at sensor 30 b). This implementation of method 80 may use more hardware (i.e. temperature sensors), but also have the benefits of being is more flexible and automatic from a control perspective. For example, the building-zone cycling step 94 in method 80 may be initiated whenever the temperature rise through a duct section exceeds 30% of the temperature drop between the supply plenum 18 (as measured by sensor 30 b) and return plenum 16 (as measured by sensor 30 a) during cooling operation. Such implementation may also take into consideration measured temperatures in the grilles 25, and may incorporate a duct efficiency model that can be used to calculate and optimize overall system efficiency.

Fan speed manipulation where fan speed is reduced less than the reduction in compressor speed or system capacity may also be incorporated in such implementation.

It is also appreciated building-zone cycling in accordance with the methods above avoids thermal losses through duct sections that are not being used at that time, and may also consider duct static pressure (e.g. via pressure sensors at sensor locations 30 c). This implementation minimizes duct thermal losses (without excessive fan power) at any given capacity while maintaining the desired limitation on heating or cooling capacity (whether to increase equipment efficiency or limit electrical power draw for demand response). Keeping the fan-speed reduction smaller than the capacity reduction reduces residence time in the ductwork and the temperature difference across the duct walls, thereby reducing duct thermal losses. However, because increasing fan speed increases sensible heat ratio, the use of this technique is constrained by higher humidity loads. Increasing fan speed also increases fan power, so the control algorithm of method 80 may be structured to determine the trade-off between fan power and delivery effectiveness.

It is appreciated that the systems and methods detailed above may factor any of the following considerations for optimization of the air handling unit 12: compressor/burner speed, cooling capacity, heating capacity, fan speed, duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature, duct R-value, duct-system layout, etc.

Results

Laboratory tests conducted to measure performance benefits of the systems and methods of the present description over existing systems.

FIG. 7 shows a plot of the measured duct delivery effectiveness (the primary driver for the reduction in performance at high temperatures) at 85° F., 95° F., 105° F. and 115° F. at varying compressor/fan speed percentages. FIG. 7 shows exemplary results for a system 10/50 having application software 42 configured for executing instructions in accordance with the method 60 of FIG. 4.

FIG. 8 shows plot of the system efficiency improvement achieved using the embodiment of method 60 (FIG. 4). For this embodiment, a complete duct system as shown in the system 50 of FIG. 3 was divided into four zones (22-28), each with a damper 20 located at the exit of the supply-air plenum 18 (i.e. adjacent to the air conditioner 12 cooling coil (not shown)). Each damper 20 was controlled manually to include or exclude that zone from the air flow leaving the air conditioner. The entire duct system was placed in a laboratory environmental chamber whose temperature was precisely controlled. The cooling energy that would be delivered to the building was measured by measuring the air flow and temperature at each supply grille 25 (entry point into the building at the end of each duct run). This experimental set-up allows the savings associated with employing the sensor-free embodiment of FIG. 3 and FIG. 4.

The results in FIG. 8 show the overall system efficiency improvements associated with synchronizing the duct-system design airflow to the desired fan flow and cooling capacity of the heat pump. The base case is to utilize the entire duct system at all capacity/fan-flow combinations. FIG. 8 shows the system efficiency improvement to range between 20% and 80% compared to operation without zoning between 60% and 25% capacity, respectively. FIG. 8 includes simulation and laboratory test data, which show that measurements agree with the model.

FIG. 9 shows a plot of the measured duct delivery effectiveness at 40% compressor speed at 85° F., 95° F., 105° F. and 115° F. at varying zone conditions: 1) no zoning, 2) 2 zones at a time, 3) 2 zones at 60% fan speed, and 4) zoning each zone individually.

FIG. 7 though FIG. 9 illustrate that the systems and methods of the present description can improve system energy efficiency by 20-300% (vs. single-zone) depending upon the design of the duct system (R-value and layout), and the temperature conditions in the duct zone.

Testing also showed that grille capacity is impacted non-uniformly, sometimes resulting in negative capacities at grilles, thereby reducing comfort.

In one embodiment, the up to 300% energy savings may be driven by delivery efficiency improvements (see 40%-capacity plot in FIG. 9). In addition, modeling shows a dramatic improvement in grille temperature uniformity relative to single-zone operation.

It is also appreciated that the technology of the present description also improves thermal comfort, as it maintains the design capacity at each grille 25, thereby maintaining the designed thermal balance of the system at reduced capacity, which is not the case when the entire duct system is utilized with reduced heating/cooling capacity.

Embodiments of the present technology may be described herein with reference to flowchart illustrations of methods and systems according to embodiments of the technology, and/or procedures, algorithms, steps, operations, formulae, or other computational depictions, which may also be implemented as computer program products. In this regard, each block or step of a flowchart, and combinations of blocks (and/or steps) in a flowchart, as well as any procedure, algorithm, step, operation, formula, or computational depiction can be implemented by various means, such as hardware, firmware, and/or software including one or more computer program instructions embodied in computer-readable program code. As will be appreciated, any such computer program instructions may be executed by one or more computer processors, including without limitation a general-purpose computer or special purpose computer, or other programmable processing apparatus to produce a machine, such that the computer program instructions which execute on the computer processor(s) or other programmable processing apparatus create means for implementing the function(s) specified.

Accordingly, blocks of the flowcharts, and procedures, algorithms, steps, operations, formulae, or computational depictions described herein support combinations of means for performing the specified function(s), combinations of steps for performing the specified function(s), and computer program instructions, such as embodied in computer-readable program code logic means, for performing the specified function(s). It will also be understood that each block of the flowchart illustrations, as well as any procedures, algorithms, steps, operations, formulae, or computational depictions and combinations thereof described herein, can be implemented by special purpose hardware-based computer systems which perform the specified function(s) or step(s), or combinations of special purpose hardware and computer-readable program code.

Furthermore, these computer program instructions, such as embodied in computer-readable program code, may also be stored in one or more computer-readable memory or memory devices that can direct a computer processor or other programmable processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory or memory devices produce an article of manufacture including instruction means which implement the function specified in the block(s) of the flowchart(s). The computer program instructions may also be executed by a computer processor or other programmable processing apparatus to cause a series of operational steps to be performed on the computer processor or other programmable processing apparatus to produce a computer-implemented process such that the instructions which execute on the computer processor or other programmable processing apparatus provide steps for implementing the functions specified in the block(s) of the flowchart(s), procedure (s) algorithm(s), step(s), operation(s), formula(e), or computational depiction(s).

It will further be appreciated that the terms “programming” or “program executable” as used herein refer to one or more instructions that can be executed by one or more computer processors to perform one or more functions as described herein. The instructions can be embodied in software, in firmware, or in a combination of software and firmware. The instructions can be stored local to the device in non-transitory media, or can be stored remotely such as on a server, or all or a portion of the instructions can be stored locally and remotely. Instructions stored remotely can be downloaded (pushed) to the device by user initiation, or automatically based on one or more factors.

It will further be appreciated that as used herein, that the terms processor, hardware processor, computer processor, central processing unit (CPU), and computer are used synonymously to denote a device capable of executing the instructions and communicating with input/output interfaces and/or peripheral devices, and that the terms processor, hardware processor, computer processor, CPU, and computer are intended to encompass single or multiple devices, single core and multicore devices, and variations thereof.

From the description herein, it will be appreciated that the present disclosure encompasses multiple embodiments which include, but are not limited to, the following:

1. An apparatus for optimizing system efficiency and demand response performance of an air-handling system, the air-handling system comprising a duct system having a plurality of duct sections and one or more dampers for controlling distribution of air into the plurality of duct sections, the apparatus comprising: (a) a system controller coupled to the one or more dampers; and (b) said system controller comprising a processor and a non-transitory memory storing instructions executable on the processor to perform steps comprising: (i) acquiring one or more operational parameters associated with the air-handling system; (ii) selectively controlling the one or more dampers based on the one or more operational parameters such that that airflow is only directed through selected duct sections of the one or more duct sections and not through the entire duct system simultaneously; and (iii) maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section in which airflow is directed to optimize one or more of system efficiency and demand response performance of the air-handling system.

2. The apparatus or method of any preceding or subsequent embodiment, wherein the air handling system further comprises a compressor or burner for conditioning the airflow and a fan for distributing airflow into the one or more duct sections, and each of the one or more duct sections corresponds with a zone to be conditioned: wherein maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section comprises adjusting one or more of a speed of the fan and a speed of the compressor or burner to a fraction of a 100% operation flow represented by a zone when only one zone is being called for conditioning or to a fraction of the 100% operation flow represented by a sum of all zones being called for conditioning.

3. The apparatus or method of any preceding or subsequent embodiment: wherein the one or more operational parameters comprise a call for capacity reduction from the air-handling unit or a utility supplying power to the air-handling unit; and wherein selectively controlling one or more dampers comprises determining if the capacity reduction that is called for is less than a sum of a capacity of two or more zones presently being called for conditioning, and cycling the airflow to the duct sections corresponding to the two or more zones such that only one of the two or more zones is receiving distributed airflow at any given time during the call for capacity reduction.

4. The apparatus or method of any preceding or subsequent embodiment, wherein three zones are being called for conditioning, and wherein cycling the airflow to the duct sections comprises: controlling the one or more dampers such that airflow is delivered to a first duct section corresponding to a first zone while airflow is restricted to second and third duct sections for a first period of time, airflow is delivered to a second duct section corresponding to a second zone while airflow is restricted to first and third duct sections for a second period of time, and airflow is delivered to a third duct section corresponding to a third zone while airflow is restricted to first and second and third duct sections for a third period of time.

5. The apparatus or method of any preceding or subsequent embodiment: wherein the one or more operational parameters comprises one or more temperature readings from sensors located within the air-handling system and coupled to the controller; wherein cycling of the airflow to the duct sections is only performed if a temperature effect threshold is not met, the temperature effect threshold being a function of the one or more temperature readings.

6. The apparatus or method of any preceding or subsequent embodiment, wherein the temperature effect threshold is a function of one or more of measured temperatures from sensors located in the one or more ducts, a predicted duct-zone temperature, or a duct R-value.

7. The apparatus or method of any preceding or subsequent embodiment, wherein the temperature effect threshold is a function of one or more of a measured temperature variation through a duct section, a measured temperature variation between a supply plenum and a return plenum of the duct system, or a temperature at one or more the grilles distributing airflow from the one or more duct sections.

8. The apparatus or method of any preceding or subsequent embodiment, wherein the capacity of two or more zones is selected from the group consisting of: compressor or burner speed, fan speed, cooling capacity, or heating capacity.

9. The apparatus or method of any preceding or subsequent embodiment, wherein the capacity of two or more zones is selected from the group consisting of: duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.

10. The apparatus or method of any preceding or subsequent embodiment, further comprising: manipulating fan speed so as to decrease fan speed less than a specified decrease in compressor or burner speed or decrease in system capacity associated with the call for capacity reduction.

11. A method for optimizing system efficiency and demand response performance of an air-handling system the air-handling system comprising a duct system having a plurality of duct sections and one or more dampers for controlling distribution of air into the plurality of duct sections, the method comprising: acquiring one or more operational parameters associated with the air-handling system; selectively controlling the one or more dampers based on the one or more operational parameters such that that airflow is only directed through selected duct sections of the one or more duct sections and not through the entire duct system simultaneously; and maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section in which airflow is directed to optimize one or more of system efficiency and demand response performance of the air-handling system; wherein said method is performed by a processor executing instructions stored on a non-transitory medium.

12. The apparatus or method of any preceding or subsequent embodiment, wherein the air handling system further comprises a compressor or burner for conditioning the airflow and a fan for distributing airflow into the one or more duct sections, and each of the one or more duct sections corresponds with a zone to be conditioned: wherein maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section comprises adjusting one or more of a speed of the fan and a speed of the compressor or burner to a fraction of a 100% operation flow represented by a zone when only one zone is being called for conditioning or to a fraction of the 100% operation flow represented by a sum of all zones being called for conditioning.

13. The apparatus or method of any preceding or subsequent embodiment: wherein the one or more operational parameters comprise a call for capacity reduction from the air-handling unit or a utility supplying power to the air-handling unit; and wherein selectively controlling one or more dampers comprises determining if the capacity reduction that is called for is less than a sum of a capacity of two or more zones presently being called for conditioning, and cycling the airflow to the duct sections corresponding to the two or more zones such that only one of the two or more zones is receiving distributed airflow at any given time during the call for capacity reduction.

14. The apparatus or method of any preceding or subsequent embodiment, wherein three zones are being called for conditioning, and wherein cycling the airflow to the duct sections comprises: controlling the one or more dampers such that airflow is delivered to a first duct section corresponding to a first zone while airflow is restricted to second and third duct sections for a first period of time, airflow is delivered to a second duct section corresponding to a second zone while airflow is restricted to first and third duct sections for a second period of time, and airflow is delivered to a third duct section corresponding to a third zone while airflow is restricted to first and second and third duct sections for a third period of time.

15. The apparatus or method of any preceding or subsequent embodiment: wherein the one or more operational parameters comprises one or more temperature readings within the air-handling system; wherein cycling of the airflow to the duct sections is only performed if a temperature effect threshold is not met, the temperature effect threshold being a function of the one or more temperature readings.

16. The apparatus or method of any preceding or subsequent embodiment, wherein the temperature effect threshold is a function of one or more of measured temperatures from sensors located in the one or more ducts, a predicted duct-zone temperature, or a duct R-value.

17. The apparatus or method of any preceding or subsequent embodiment, wherein the temperature effect threshold is a function of one or more of a measured temperature variation through a duct section, a measured temperature variation between a supply plenum and a return plenum of the duct system, or a temperature at one or more the grilles distributing airflow from the one or more duct sections.

18. The apparatus or method of any preceding or subsequent embodiment, wherein the capacity of two or more zones is selected from the group consisting of: compressor or burner speed, fan speed, cooling capacity, or heating capacity.

19. The apparatus or method of any preceding or subsequent embodiment, wherein the capacity of two or more zones is selected from the group consisting of: duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.

20. The apparatus or method of any preceding or subsequent embodiment, further comprising: manipulating fan speed so as to decrease fan speed less than a specified decrease in compressor or burner speed or decrease in system capacity associated with the call for capacity reduction.

21. An air-handling system optimized for efficiency and demand response performance, comprising: (a) an air-handling unit; (b) a duct system coupled to the air handling unit, the duct system comprising a plurality of duct sections and one or more dampers for controlling distribution of air into the plurality of duct sections, the apparatus comprising: (c) a system controller coupled to the one or more dampers and air handling unit; and (d) said system controller comprising a processor and a non-transitory memory storing instructions executable on the processor to perform steps comprising: (i) acquiring one or more operational parameters associated with the air-handling system; (ii) selectively controlling the one or more dampers based on the one or more operational parameters such that that airflow is only directed through selected duct sections of the one or more duct sections and not through the entire duct system simultaneously; and (iii) maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section in which airflow is directed to optimize one or more of system efficiency and demand response performance of the air-handling system.

22. The apparatus or method of any preceding or subsequent embodiment, wherein the air handling unit further comprises a compressor or burner for conditioning the airflow and a fan for distributing airflow into the one or more duct sections, and each of the one or more duct sections corresponds with a zone to be conditioned: wherein maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section comprises adjusting one or more of a speed of the fan and a speed of the compressor or burner to a fraction of a 100% operation flow represented by a zone when only one zone is being called for conditioning or to a fraction of the 100% operation flow represented by a sum of all zones being called for conditioning.

23. The apparatus or method of any preceding or subsequent embodiment: wherein the one or more operational parameters comprise a call for capacity reduction from the air-handling unit or a utility supplying power to the air-handling unit; and wherein selectively controlling one or more dampers comprises determining if the capacity reduction that is called for is less than a sum of a capacity of two or more zones presently being called for conditioning, and cycling the airflow to the duct sections corresponding to the two or more zones such that only one of the two or more zones is receiving distributed airflow at any given time during the call for capacity reduction.

24. The apparatus or method of any preceding or subsequent embodiment, wherein three zones are being called for conditioning, and wherein cycling the airflow to the duct sections comprises: controlling the one or more dampers such that airflow is delivered to a first duct section corresponding to a first zone while airflow is restricted to second and third duct sections for a first period of time, airflow is delivered to a second duct section corresponding to a second zone while airflow is restricted to first and third duct sections for a second period of time, and airflow is delivered to a third duct section corresponding to a third zone while airflow is restricted to first and second and third duct sections for a third period of time.

25. The apparatus or method of any preceding or subsequent embodiment, further comprising one or more sensors located within the air handling system and coupled to the system controller: wherein the one or more operational parameters comprises one or more temperature readings from the one or more sensors within the air-handling system; wherein cycling of the airflow to the duct sections is only performed if a temperature effect threshold is not met, the temperature effect threshold being a function of the one or more temperature readings.

26. The apparatus or method of any preceding or subsequent embodiment, wherein the temperature effect threshold is a function of one or more of measured temperatures from sensors located in the one or more ducts, a predicted duct-zone temperature, or a duct R-value.

27. The apparatus or method of any preceding or subsequent embodiment, wherein the temperature effect threshold is a function of one or more of a measured temperature variation through a duct section, a measured temperature variation between a supply plenum and a return plenum of the duct system, or a temperature at one or more the grilles distributing airflow from the one or more duct sections.

28. The apparatus or method of any preceding or subsequent embodiment, wherein the capacity of two or more zones is selected from the group consisting of: compressor or burner speed, fan speed, cooling capacity, or heating capacity.

29. The apparatus or method of any preceding or subsequent embodiment, wherein the capacity of two or more zones is selected from the group consisting of: duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.

30. The apparatus or method of any preceding or subsequent embodiment, further comprising: manipulating fan speed so as to decrease fan speed less than a specified decrease in compressor or burner speed or decrease in system capacity associated with the call for capacity reduction.

31. A method for optimizing system efficiency and demand response performance for variable-fan-speed and variable-capacity air handling systems, the method comprising: (a) sensing system operational parameters selected from the group consisting of compressor speed, cooling capacity, heating capacity, fan speed, duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature; (b) selectively controlling building-zone dampers such that air flows through selected duct sections and not through the entire duct system simultaneously, wherein design velocity in each duct section is roughly maintained whenever the duct section is being used; (c) using measured or predicted duct-zone temperature, duct R-value, and optionally duct-system layout, to determine when to flow air through a duct section in step (b); and (d) optionally decreasing indoor fan speed less than the desired decrease in compressor speed or system capacity; (e) wherein said method is performed by a system controller.

32. The apparatus or method of any preceding or subsequent embodiment, wherein said system controller comprises a processor and a non-transitory memory storing instructions executable by the processor to perform said method.

33. The apparatus or method of any preceding or subsequent embodiment, wherein said selectively controlling building-zone dampers such that air flows through selected duct sections comprises cycling the building-zone dampers between open and closed positions sequentially through all said zones calling for conditioning.

34. A system for optimizing system efficiency and demand response performance for variable-fan-speed and variable-capacity furnace, heat pump, and air conditioning systems, the system comprising: (a) a system controller; and (b) a plurality of sensors; (c) wherein said system controller and said sensors are configured to perform steps comprising: (I) sensing system operational parameters selected from the group consisting of compressor speed, cooling capacity, heating capacity, fan speed, duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature; (ii) selectively controlling building-zone dampers such that air flows through selected duct sections and not through the entire duct system simultaneously, wherein design velocity in each duct section is roughly maintained whenever the duct section is being used; (iii) using measured or predicted duct-zone temperature, duct R-value, and optionally duct-system layout, to determine when to flow air through a duct section in step (b); and (iv) optionally decreasing indoor fan speed less than the desired decrease in compressor speed or system capacity.

35. The apparatus or method of any preceding or subsequent embodiment, wherein said system controller comprises: a processor; and a non-transitory memory storing instructions executable by the processor.

36. The apparatus or method of any preceding or subsequent embodiment, wherein said selectively controlling building-zone dampers such that air flows through selected duct sections comprises cycling the building-zone dampers between open and closed positions sequentially through all said zones calling for conditioning.

As used herein, the singular terms “a,” “an,” and “the” may include plural referents unless the context clearly dictates otherwise. Reference to an object in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.”

As used herein, the term “set” refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects.

As used herein, the terms “substantially” and “about” are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation. When used in conjunction with a numerical value, the terms can refer to a range of variation of less than or equal to ±10% of that numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, “substantially” aligned can refer to a range of angular variation of less than or equal to ±10°, such as less than or equal to ±5°, less than or equal to ±4°, less than or equal to ±3°, less than or equal to ±2°, less than or equal to ±1°, less than or equal to ±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.

Additionally, amounts, ratios, and other numerical values may sometimes be presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be understood flexibly to include numerical values explicitly specified as limits of a range, but also to include all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and so forth.

Although the description herein contains many details, these should not be construed as limiting the scope of the disclosure but as merely providing illustrations of some of the presently preferred embodiments. Therefore, it will be appreciated that the scope of the disclosure fully encompasses other embodiments which may become obvious to those skilled in the art.

All structural and functional equivalents to the elements of the disclosed embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed as a “means plus function” element unless the element is expressly recited using the phrase “means for”. No claim element herein is to be construed as a “step plus function” element unless the element is expressly recited using the phrase “step for”. 

What is claimed is:
 1. An apparatus for optimizing system efficiency and demand response performance of an air-handling system, the air-handling system comprising a duct system having a plurality of duct sections and one or more dampers for controlling distribution of air into the plurality of duct sections, the apparatus comprising: (a) a system controller coupled to the one or more dampers; and (b) said system controller comprising a processor and a non-transitory memory storing instructions executable on the processor to perform steps comprising: (i) acquiring one or more operational parameters associated with the air-handling system; (ii) selectively controlling the one or more dampers based on the one or more operational parameters such that that airflow is only directed through selected duct sections of the one or more duct sections and not through the entire duct system simultaneously; and (iii) maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section in which airflow is directed to optimize one or more of system efficiency and demand response performance of the air-handling system.
 2. The apparatus of claim 1, wherein the air handling system further comprises a compressor or burner for conditioning the airflow and a fan for distributing airflow into the one or more duct sections, and each of the one or more duct sections corresponds with a zone to be conditioned: wherein maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section comprises adjusting one or more of a speed of the fan and a speed of the compressor or burner to a fraction of a 100% operation flow represented by a zone when only one zone is being called for conditioning or to a fraction of the 100% operation flow represented by a sum of all zones being called for conditioning.
 3. The apparatus of claim 2: wherein the one or more operational parameters comprise a call for capacity reduction from the air-handling unit or a utility supplying power to the air-handling unit; and wherein selectively controlling one or more dampers comprises determining if the capacity reduction that is called for is less than a sum of a capacity of two or more zones presently being called for conditioning, and cycling the airflow to the duct sections corresponding to the two or more zones such that only one of the two or more zones is receiving distributed airflow at any given time during the call for capacity reduction.
 4. The apparatus of claim 3, wherein three zones are being called for conditioning, and wherein cycling the airflow to the duct sections comprises: controlling the one or more dampers such that airflow is delivered to a first duct section corresponding to a first zone while airflow is restricted to second and third duct sections for a first period of time, airflow is delivered to a second duct section corresponding to a second zone while airflow is restricted to first and third duct sections for a second period of time, and airflow is delivered to a third duct section corresponding to a third zone while airflow is restricted to first and second and third duct sections for a third period of time.
 5. The apparatus of claim 3: wherein the one or more operational parameters comprises one or more temperature readings from sensors located within the air-handling system and coupled to the controller; wherein cycling of the airflow to the duct sections is only performed if a temperature effect threshold is not met, the temperature effect threshold being a function of the one or more temperature readings.
 6. The apparatus of claim 5, wherein the temperature effect threshold is a function of one or more of measured temperatures from sensors located in the one or more ducts, a predicted duct-zone temperature, or a duct R-value.
 7. The apparatus of claim 5, wherein the temperature effect threshold is a function of one or more of a measured temperature variation through a duct section, a measured temperature variation between a supply plenum and a return plenum of the duct system, or a temperature at one or more the grilles distributing airflow from the one or more duct sections.
 8. The apparatus of claim 3, wherein the capacity of two or more zones is selected from the group consisting of: compressor or burner speed, fan speed, cooling capacity, or heating capacity.
 9. The apparatus of claim 3, wherein the capacity of two or more zones is selected from the group consisting of: duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.
 10. The apparatus of claim 3, further comprising: manipulating fan speed so as to decrease fan speed less than a specified decrease in compressor or burner speed or decrease in system capacity associated with the call for capacity reduction.
 11. A method for optimizing system efficiency and demand response performance of an air-handling system the air-handling system comprising a duct system having a plurality of duct sections and one or more dampers for controlling distribution of air into the plurality of duct sections, the method comprising: acquiring one or more operational parameters associated with the air-handling system; selectively controlling the one or more dampers based on the one or more operational parameters such that that airflow is only directed through selected duct sections of the one or more duct sections and not through the entire duct system simultaneously; and maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section in which airflow is directed to optimize one or more of system efficiency and demand response performance of the air-handling system; wherein said method is performed by a processor executing instructions stored on a non-transitory medium.
 12. The method of claim 11, wherein the air handling system further comprises a compressor or burner for conditioning the airflow and a fan for distributing airflow into the one or more duct sections, and each of the one or more duct sections corresponds with a zone to be conditioned: wherein maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section comprises adjusting one or more of a speed of the fan and a speed of the compressor or burner to a fraction of a 100% operation flow represented by a zone when only one zone is being called for conditioning or to a fraction of the 100% operation flow represented by a sum of all zones being called for conditioning.
 13. The method of claim 12: wherein the one or more operational parameters comprise a call for capacity reduction from the air-handling unit or a utility supplying power to the air-handling unit; and wherein selectively controlling one or more dampers comprises determining if the capacity reduction that is called for is less than a sum of a capacity of two or more zones presently being called for conditioning, and cycling the airflow to the duct sections corresponding to the two or more zones such that only one of the two or more zones is receiving distributed airflow at any given time during the call for capacity reduction.
 14. The method of claim 13, wherein three zones are being called for conditioning, and wherein cycling the airflow to the duct sections comprises: controlling the one or more dampers such that airflow is delivered to a first duct section corresponding to a first zone while airflow is restricted to second and third duct sections for a first period of time, airflow is delivered to a second duct section corresponding to a second zone while airflow is restricted to first and third duct sections for a second period of time, and airflow is delivered to a third duct section corresponding to a third zone while airflow is restricted to first and second and third duct sections for a third period of time.
 15. The method of claim 13: wherein the one or more operational parameters comprises one or more temperature readings within the air-handling system; wherein cycling of the airflow to the duct sections is only performed if a temperature effect threshold is not met, the temperature effect threshold being a function of the one or more temperature readings.
 16. The method of claim 15, wherein the temperature effect threshold is a function of one or more of measured temperatures from sensors located in the one or more ducts, a predicted duct-zone temperature, or a duct R-value.
 17. The method of claim 15, wherein the temperature effect threshold is a function of one or more of a measured temperature variation through a duct section, a measured temperature variation between a supply plenum and a return plenum of the duct system, or a temperature at one or more the grilles distributing airflow from the one or more duct sections.
 18. The method of claim 13, wherein the capacity of two or more zones is selected from the group consisting of: compressor or burner speed, fan speed, cooling capacity, or heating capacity.
 19. The method of claim 13, wherein the capacity of two or more zones is selected from the group consisting of: duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.
 20. The method of claim 13, further comprising: manipulating fan speed so as to decrease fan speed less than a specified decrease in compressor or burner speed or decrease in system capacity associated with the call for capacity reduction.
 21. An air-handling system optimized for efficiency and demand response performance, comprising: (a) an air-handling unit; (b) a duct system coupled to the air handling unit, the duct system comprising a plurality of duct sections and one or more dampers for controlling distribution of air into the plurality of duct sections, the apparatus comprising: (c) a system controller coupled to the one or more dampers and air handling unit; and (d) said system controller comprising a processor and a non-transitory memory storing instructions executable on the processor to perform steps comprising: (i) acquiring one or more operational parameters associated with the air-handling system; (ii) selectively controlling the one or more dampers based on the one or more operational parameters such that that airflow is only directed through selected duct sections of the one or more duct sections and not through the entire duct system simultaneously; and (iii) maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section in which airflow is directed to optimize one or more of system efficiency and demand response performance of the air-handling system.
 22. The system of claim 21, wherein the air handling unit further comprises a compressor or burner for conditioning the airflow and a fan for distributing airflow into the one or more duct sections, and each of the one or more duct sections corresponds with a zone to be conditioned: wherein maintaining one or more of design velocity, heating capacity, and cooling capacity in each duct section comprises adjusting one or more of a speed of the fan and a speed of the compressor or burner to a fraction of a 100% operation flow represented by a zone when only one zone is being called for conditioning or to a fraction of the 100% operation flow represented by a sum of all zones being called for conditioning.
 23. The system of claim 22: wherein the one or more operational parameters comprise a call for capacity reduction from the air-handling unit or a utility supplying power to the air-handling unit; and wherein selectively controlling one or more dampers comprises determining if the capacity reduction that is called for is less than a sum of a capacity of two or more zones presently being called for conditioning, and cycling the airflow to the duct sections corresponding to the two or more zones such that only one of the two or more zones is receiving distributed airflow at any given time during the call for capacity reduction.
 24. The system of claim 23, wherein three zones are being called for conditioning, and wherein cycling the airflow to the duct sections comprises: controlling the one or more dampers such that airflow is delivered to a first duct section corresponding to a first zone while airflow is restricted to second and third duct sections for a first period of time, airflow is delivered to a second duct section corresponding to a second zone while airflow is restricted to first and third duct sections for a second period of time, and airflow is delivered to a third duct section corresponding to a third zone while airflow is restricted to first and second and third duct sections for a third period of time.
 25. The system of claim 23, further comprising one or more sensors located within the air handling system and coupled to the system controller: wherein the one or more operational parameters comprises one or more temperature readings from the one or more sensors within the air-handling system; wherein cycling of the airflow to the duct sections is only performed if a temperature effect threshold is not met, the temperature effect threshold being a function of the one or more temperature readings.
 26. The system of claim 25, wherein the temperature effect threshold is a function of one or more of measured temperatures from sensors located in the one or more ducts, a predicted duct-zone temperature, or a duct R-value.
 27. The system of claim 25, wherein the temperature effect threshold is a function of one or more of a measured temperature variation through a duct section, a measured temperature variation between a supply plenum and a return plenum of the duct system, or a temperature at one or more the grilles distributing airflow from the one or more duct sections.
 28. The system of claim 23, wherein the capacity of two or more zones is selected from the group consisting of: compressor or burner speed, fan speed, cooling capacity, or heating capacity.
 29. The system of claim 23, wherein the capacity of two or more zones is selected from the group consisting of: duct-section air flow, zone air flow, duct-inlet temperature, duct-outlet temperature, and duct-zone temperature.
 30. The system of claim 23, further comprising: manipulating fan speed so as to decrease fan speed less than a specified decrease in compressor or burner speed or decrease in system capacity associated with the call for capacity reduction. 